I have an update: Exit 85 & 86 signage along I-540 has been replaced (for the most part... not complete yet). Apparently, now, AR 12 is routed along Walton Blvd (US 71B) in Bentonville east to I-540, then north along 540 to Exit 86 (SE 14th St/Hudson Rd), then to the east along US 62. This, all according to the new BGS's for Exit 85 and Exit 86 that were just recently put up. I'm not sure of the routing of AR 12 off of US 62... I may go investigate tomorrow.
Also to note: On the BGSs at Exit 85, the "B" in the US 71B shield is full-size. I also noticed a AR 12 shield on a northbound BGS that was in a 3-di AR shield for Exit 86. Honestly, the signage looks really bad. I was liking the Clearview, but someone f'ed up these ones.